Abstract: Under the influence of complex geological structure and strong engineering disturbance,the surrounding rock of roadway shows significant nonlinear large deformation characteristics,and the problems such as serious floor heave and fail ure of support system are increasingly prominent.Taking the track downhill roadway in the fifth mining area of Leji barite mine as the research object,the floor stress distribution characteristics and floor failure depth under complex stress environment are analyzed through the floor heave mechanical model.The numerical model is established to calculate the stress and strain state of the floor.The failure depth of the floor is highly consistent between the theoretical analysis and the numerical calculation re sults.For the differential rock stratum structure of the cross-layer roadway,according to the different lithology of the floor,targe ted control measures are formulated and applied to the engineering site.Practice has proved that the classification support strat egy can effectively limit the deformation of surrounding rock.The monitoring results show that the maximum damage of floor heave is 35.6 mm,which is within a reasonable range.The effective control of floor heave shows that the proposed classification support scheme is reasonable,which provides scientific guarantee for guiding safe and efficient mining on site.

Key words: cross-layer roadway,floor deformation,floor control technology,complex geological conditions